If you believe that 'faster' is raising conflicts due its own internal data structures (OOBTree bucket splits), rather than in the application-dveined session data, there is a conflict-free alternative available: we found that it was slower than the other, and therefore didn't scale as well, even given the possibility of conflicts.
To enable the conflict-free storage, you need to patch the '_BUCKET_TYPE' class-level variable of the storage to use 'AppendOnlyDict' rather than 'OOBTree'. E.g.:
from Products.faster.sessiondata import CBSessionDataContainer from Products.faster.appendict import AppendOnlyDict CBSessionDataContainer._BUCKET_TYPE = AppendOnlyDict
I've changed to: _BUCKET_TYPE = AppendOnlyDict in sessiondata.py for SessionDataContainer and CBSessionDataContainer. Unfortunatelly when I run external method like below concurrently from 3 different browsers (Opera, FF, Konqueror) I still get conflict errors. import time def testme(self): print 'testme started' self.REQUEST.SESSION time.sleep(50) print 'testme after sleep' return 'finished' Faster 'Resolution secs' is set to 20. Console output: 2007-04-12 10:31:50 DEBUG txn.-1260708960 new transaction testme started 2007-04-12 10:31:51 DEBUG txn.-1277494368 new transaction testme started 2007-04-12 10:31:54 DEBUG txn.-1252316256 new transaction testme started testme after sleep 2007-04-12 10:32:40 DEBUG txn.-1260708960 commit <Connection at b562e9ac> 2007-04-12 10:32:40 DEBUG txn.-1260708960 commit testme after sleep 2007-04-12 10:32:41 INFO ZPublisher.Conflict ConflictError at /testme: database conflict error (oid 0x2b, class Products.faster.sessiondata.SessionDataContainer, serial this txn started with 0x036ce4767ce55799 2007-04-12 08:22:29.272469, serial currently committed 0x036ce480ad6d3044 2007-04-12 08:32:40.646840) (3 conflicts (0 unresolved) since startup at Thu Apr 12 10:17:09 2007) 2007-04-12 10:32:41 DEBUG txn.-1277494368 abort 2007-04-12 10:32:41 DEBUG txn.-1277494368 new transaction testme started testme after sleep 2007-04-12 10:32:44 INFO ZPublisher.Conflict ConflictError at /testme: database conflict error (oid 0x2b, class Products.faster.sessiondata.SessionDataContainer, serial this txn started with 0x036ce4767ce55799 2007-04-12 08:22:29.272469, serial currently committed 0x036ce480ad6d3044 2007-04-12 08:32:40.646840) (4 conflicts (0 unresolved) since startup at Thu Apr 12 10:17:09 2007) 2007-04-12 10:32:45 DEBUG txn.-1252316256 abort 2007-04-12 10:32:45 DEBUG txn.-1252316256 new transaction testme started testme after sleep 2007-04-12 10:33:31 DEBUG txn.-1277494368 commit <Connection at b62a8d8c> 2007-04-12 10:33:31 DEBUG txn.-1277494368 commit testme after sleep 2007-04-12 10:33:35 DEBUG txn.-1252316256 commit <Connection at b55b982c> 2007-04-12 10:33:35 DEBUG txn.-1252316256 commit Also after few different tires, eg. with Resolution secs == 300 I ecountered conflicts with AppendOnlyDict like: 2007-04-12 10:53:07 INFO ZPublisher.Conflict ConflictError at /testme: database conflict error (oid 0x4c, class Products.faster.appendict.AppendOnlyDict, serial this txn started with 0x036ce49409621366 2007-04-12 08:52:02.199166, serial currently committed 0x036ce49515ed0477 2007-04-12 08:53:05.138871) (9 conflicts (0 unresolved) since startup at Thu Apr 12 10:17:09 2007) Is there a point in faster where I can put debug message to see that bucket splits (or something like that) happened? -- Maciej Wisniowski